I have a 98 Cannondale T700 (touring bike). It's always been a bit creaky, but now it's ridiculous. It sounds kind of like I'm grinding my teeth, but louder. I cleaned the chain and tried to check for loose screws in case I could see anything. I keep thinking it might be the bottom bracket, although the cranks don't slip at all. I cleaned the outside of the bottom bracket, but I haven't taken it out or replaced it. Do I need to? Does anyone know about this kind of sound, what might be the problem and would I be able to fix it myself?